Building closures typically include a frame for mounting within a building wall structure opening and at least one closure unit, such as a window or sliding door unit, for mounting within the frame. The frame has an exterior nailing flange for securing the frame to the building wall structure. Moisture can enter the cavity between the closure frame and the surrounding wall opening and pass into the building interior due to air pressure dynamics on the closure. A general object of the present disclosure is to provide a mechanism by means of which such passage of moisture to the building interior is retarded, and moisture is collected and drained to the building exterior.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A building closure for mounting within an opening in a building wall structure, in accordance with one aspect of the present disclosure, includes a frame for mounting within the wall structure opening and at least one closure unit for mounting within the frame. The frame has at least one interior chamber extending entirely around the frame and a nailing flange for securement to the building wall structure such that at least a portion of the frame is disposed within the building wall opening. There is a cavity between at least one exterior surface of the frame and the inner periphery of the building wall opening, with the cavity extending along at least a top portion of the frame. A barrier extends along at least the top portion of the frame to retard passage of moisture from the cavity to the building interior. At least one moisture weep opening is disposed in the top portion of the frame from the cavity to the interior chamber of the frame such that moisture in the cavity flows through the weep opening into the chamber, within the chamber around the frame and then out of a drain opening in a bottom portion of the frame.
The barrier preferably includes a wall extending from at least the top portion of the frame toward the inner periphery of the building wall opening. The wall in an exemplary embodiment of the disclosure includes a flexible seal wall carried by at least the top portion of the frame for engagement with the inner periphery of the building opening. The flexible seal wall preferably extends along top and side portions of the frame toward the inner periphery of the building wall. There preferably also is a seal on an inner surface of the nailing flange for engagement with an opposing surface of the building wall structure to retard ingress of moisture between the nailing flange and the building wall structure into the cavity.